Alkoxysilyl-containing silane and siloxane compounds are widely used in paint and coating applications. When these alkoxysilyl-containing siloxane compounds are blended with curing catalysts, alkoxy groups react at normal temperature to form a siloxane network. Coatings having heat resistance and weather resistance can be readily formed. They are thus used in a wide variety of applications covering from outdoor buildings to electronic parts.
Such alkoxysilyl-containing siloxane compounds are generally prepared by partial hydrolysis of alkoxysilanes as described in Patent Documents 1 to 3. However, the alkoxy-containing siloxane compounds have the drawback of a low cure rate. It is believed that highly active alkoxy groups are consumed during hydrolysis reaction while less active alkoxy groups are left behind. Thus the subsequent cure reaction proceeds at a low rate.
Patent Document 4 discloses another method for preparing an alkoxysilyl-containing siloxane compound by hydrosilylation reaction of a silicone compound containing a hydrosilyl group with a compound containing both an olefin and an alkoxysilyl group. Even when siloxane compounds are produced by this method, no significant improvements in reaction rate are observed.
Patent Document 5 proposes to use an alkoxysilyl-containing cyclic siloxane compound as an insulating film-forming material. Although the cyclic siloxane compound contains many active alkoxysilyl groups, no significant improvements in reaction rate are observed over ordinary alkoxysilanes.
A coating composition comprising a low-molecular-weight alkoxysilyl-containing silane or siloxane compound such as tetramethoxysilane is highly reactive and cures within 15 minutes in an environment of 25° C. and 50% RH, for example. However, its coating is brittle and has mechanical properties insufficient to withstand use as coating film, as demonstrated by cracking in the course of curing.